Preheat oven to 400. Butter a shallow 10 cup enameled cast iron, or glass baking dish. Heat the oil in a small frying pan. Add the scallions and cook over moderately high heat, stirring frequently, until softened, about 1 minute longer. Spread the mixture in the prepared baking dish and arrange the shrimp on top. Sprinkle with tomatoes and feta. In a bowl, beat the eggs with the dill, hot pepper sauce, salt, and black pepper. Beat in the cream. Spoon the custard over the shrimp; the shrimp should be at least halfway covered with custard. Sprinkle with the Parmesan. Bake for about 17 minutes, until the custard is set and the shrimp are cooked through. Let the casserole stand for 5 minutes before seving.